gauge located at Bay City, Texas. Its maximum and minimum annual discharge volumes 

 were 3,812,800 and 344,000 acre-ft, respectively 



New Sundown 



o^5^^^^ 



Island 



ofO?5>^ 



(proposed) 



^\z>y^ 



•^* 



^^ y" 



\ '/^ 



^^ y^ 





.f^ 





sta1 ^^ 



Port /^\ 



jL'^^'^^ < 



O'Conner/ N. 



--^^ x.^^^' /<^ 



/ / .^^x 



• _• ^o-*""^ /^ 



f /^-^^""'"^ sta 2 - 









J Legend 



^X\. ^ y^ 



\ 



' Numerical Stations • 



/? aSs. y' 







^ -^ ^~\/ -W- 



Scale 



/<: ' • y'~\^ ^C 



2000 



r >^ \ N 





\ llllll 1 1 -, 



1 Meters /^' 



,'y>^ ^V. 





1 /T 



>^ \ 



/■•' 



-/^ Matagorda 



,o^°^ J- y 



Ship Channel 



"^ 9^- p-' ./ 







Gulf of Mexico 



Figure 21 . Locations of deployed current meters and numerical gauges 



Lavaca River enters Lavaca Bay at its northeast comer, and, prior to 1980, had an 

 annual discharge volume of 795,900 acre-ft (Mueller and Matthews 1987). The 

 maximum and minimum annual discharge volumes were 2,023,900 and 133,900 acre-ft, 

 respectively. In 1980, the Palmetto Bend Dam, forming Lake Texana, was constructed 

 on the lower Navidad River, which is a major tributary to the Lavaca River. The dam 

 reduced the discharge volume of Lavaca River by 92,000 acre-ft annually. 



Harwood (1973) investigated whether the inflow of the Lavaca and Colorado Rivers 

 increases the ebb flow in Matagorda Bay by increasing the water-surface gradient from 

 the bay to the open gulf. After examining stream gauging records and estimating that the 

 total discharge from the two rivers was 10,000 cfs, Harwood (1973) concluded that, 

 except during major floods, the combined river flows add less than 0. 1 ft to the water- 

 surface elevation in a 24-hr period (the diurnal tidal period). Because the mean tidal 

 range at Port Lavaca is about 0.8 ft, for the present study, river inflows to the bay were 

 judged to make a minimal contribution to the circulation within the bay. Therefore, the 



26 



Chapter 3 Circulation Modeling 



